906 THE BELL SYSTEM TECHNICAL JOURNAL, OCTOBER 1951 



we find that there is a diffraction band lying in the range of negative values 

 of £, and extending more or less near to the point E = 0^. We shall call this 

 di fictitious di fraction hand. Now it is immediately clear that the complicated 

 behavior of our curves arises from the fact that the small positive (and hence 

 physically significant) values of E concerned are near the upper edge of the 

 fictitious diffraction band. 



8 Specifically, what is meant is that there is such a range of values of E in which the 

 exponent n is real. 



